JP3378636B2 - Sound absorbing concrete and its secondary products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-absorbing concrete and its secondary product, particularly a sound-absorbing concrete suitable as a soundproof material for various traffic noises and noises generated from factories and the like, and a concrete plate formed using the same. .

[0002]

2. Description of the Related Art Conventionally, as sound absorbing concrete boards used as soundproof materials for various noises, there are known ALC boards having continuous voids, concrete boards using lightweight aggregate or crushed stone.

[0003]

[Problems to be Solved by the Invention] By the way, the former AL
C plate requires heat for autoclave curing at the time of manufacturing, is not only expensive to manufacture, but also weak in strength. In this case, there is a problem that the voids tend to be clogged with soot and dust in the exhaust gas, and the sound absorbing effect deteriorates for a long period of time.

Further, the latter concrete plate is made by simply combining aggregates with a cement-based binder, which is extremely heavy and inconvenient to handle.
There is a problem of low sound absorption.

Therefore, an object of the present invention is to provide a sound absorbing concrete secondary product which can be manufactured with low energy without using heat, has a low bulk specific gravity, is easy to handle, has excellent sound absorbing properties, and has relatively high strength. It is in.

[0006]

In order to solve the above problems, the first invention uses water, cement, a bubble generating agent, and a water reducing agent as a main material, and in some cases, a polymer emulsion, an acrylic type or A viscous polymer-based mixture such as cellulosic or a mixture of finely divided pozzolanic substances is used as a binder, and the inter-aggregate voids 15 to 5 are used.
By combining the aggregates with 0% of the binder, continuous voids are formed between the aggregates, and the binder has a void inside due to foaming.

The second invention is that water, cement, and
A foaming agent or water-reducing agent is used, and in some cases, a polymer emulsion, a viscous polymer-based mixture such as an acrylic or cellulose-based material, or a fine-grained pozzolanic substance is added to form a mixture, Between the material gap 15 ~
A structure in which a molded body is formed by bonding aggregates using 50% of the binder, and continuous voids are formed between the aggregates, and the binder has voids inside due to foaming. It was done.

In the present invention, the aggregate has a large irregularity on the surface selected from volcanic rubble, pumice stone and artificial lightweight aggregate, and the internal voids of this aggregate and the voids of the binder communicate with each other. It can also have a structure.

It is also possible to mix or lay a fibrous material in the binder, or to change the plate thickness of the plate-like body formed by bonding the aggregate with the binder by the unevenness of the surface.

[0010]

[Operation] Since the continuous void is formed by the binder that binds the aggregate, the energy of the sound wave enters the continuous void and is rubbed against the surface of the void to be converted into thermal energy. As a result, the sonic energy penetrates into this void and causes some resonance in the void and is effectively absorbed.

Further, when the aggregate having a continuous void inside is used, the sound wave energy penetrates into the inside of the aggregate and the sound absorbing performance is further enhanced.

Furthermore, when the fiber material is dispersed and mixed or continuous fibers are laid, the acoustic energy hits the fibers traversing the voids, the acoustic energy is converted into vibration energy, and the sound absorbing performance is further improved.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 (A), 1 (B) and 1 (C), a binder 2 for joining aggregates 1 to form a concrete plate is mainly composed of cement, water and air bubbles. Agent,
Formed by using a high-performance water reducing agent or an AE water reducing agent, and in some cases, adding a polymer emulsion, a viscous polymer-based mixture such as an acrylic type or a cellulosic type, or a fine-grained pozzolanic substance and mixing them. 1 of the inter-aggregate voids (excluding the internal voids of the aggregate itself)
Using the binder 2 in an amount of 5 to 50%, the binder 2 is sprinkled with the binder 2 by evenly mixing the binder 2 and the aggregate 1, and thus the binder 1 is bonded with the binder 2. Concrete having continuous voids 3 is formed between the binders 2 enclosing the aggregate 1, and the concrete is formed into a compact to form a concrete plate.

The aggregate 1 is selected from volcanic rubble, pumice stone, and artificial lightweight aggregate and has a large surface irregularity. In addition, this unevenness is preferably 0.3 mm or more.

Although the aggregate shown in FIG. 1 (A) has no voids inside, the aggregate 1 shown in FIGS. 1 (B) and 1 (C) has continuous voids inside, like shirasu pumice stone. The one having 1a is used.

The binding material 2 is in a state of wrapping the surface of each aggregate 1 with a substantially uniform thickness, foams by mixing the bubble generating agent, and has continuous voids 2a, and the surface thereof is uneven. become.

As shown in FIGS. 1B and 1C, when the aggregate 1 having the voids 1a is used, the voids 2a of the binding material 2 are used.
And the void 1a of the aggregate 1 communicate with each other.

In FIG. 1 (C), a fibrous material 4 is added to a binding material 2.
Are mixed or laid to improve the sound absorbing performance, and the preferred dimensions of the fibrous material 4 are 5 to 10 μm in diameter and 2 in length.
~ 7 mm.

When the amount of the binder 2 with respect to the aggregate 1 is 15% or less of the inter-aggregate void, the bond strength becomes weak, and when it is 50% or more, a sufficient amount of the continuous void 3 is secured. Becomes impossible.

FIG. 2 shows an example of a concrete plate 5 formed by using concrete formed by joining aggregates 1 with a binder 2. , The thickness of the concrete board 5 to the convex portion 6
And the concave portion 7 are alternately changed to improve the sound absorbing effect.

The concrete of the present invention and the secondary product using the same have the above-mentioned constitution, and the concrete plate as illustrated in FIG. 2 is formed by molding the concrete in which the aggregate 1 is bonded by the bonding material 2. 5 is formed and used as a soundproof material constituting a soundproof wall for various traffic noises, factory noises, and the like.

When the concrete board 5 is used as a soundproof material, since it has the continuous voids 3, the energy of the sound wave enters the continuous voids 3 and is rubbed with the surface of the combined body 2 to be converted into thermal energy. Sound absorption effect occurs.

Since the surface of the combined body 2 forming the periphery of the continuous void 3 is uneven, the sound absorbing effect is excellent, and the combined body 2 has the continuous void 2a formed by foaming and the aggregate 1 has When the one having the continuous voids 1a is used, the sound wave energy also penetrates into the continuous voids 1a of the aggregate 1 through the voids 2a, and the continuous voids 2a and the continuous voids 1a generate a sound absorbing action to further reduce the sound absorption. The effect is improved.

Note that concrete can be directly used for forming a soundproof wall by in-situ casting.

Further, when the fibrous material 4 is mixed or laid in the binder 2, sonic energy hits the fibers traversing the continuous void 3 and the continuous void 2a and converts the acoustic energy into vibration energy. As a result, the sound absorbing effect is further improved.

[0027]

[Embodiment 1] Next, a specific method for producing the sound absorbing concrete plate of the present invention and its characteristics will be described.

As the binder, a mixture of water, ordinary cement, aluminum powder as a bubble generating agent, and a naphthalene type high-performance water reducing agent was used. The ratio of them is water: 25 wt
%, Cement: 100 wt%, foam generating agent: 1 wt%,
High-performance water reducing agent: 1 wt% The properties of the binder are such that the aggregate is sprinkled with a suitable viscosity state (yield value: 0.6 g / cm ² , plastic viscosity: 20-30 po
was used). This can be adjusted by the addition amount of the high performance water reducing material.

Pumice stone from Kagoshima (particle size: 2.4-4.0 mm, apparent specific gravity:
1.23 and porosity 46.0%) were used.

The mixing ratio of the aggregate and the binder was the amount of the binder that filled 20% by volume of the aggregate voids (excluding the voids of the single particle aggregate).

In the manufacturing method, a predetermined amount of aggregate and binder were weighed, and concrete stirred by a forced mixer was poured into a plate-shaped mold having irregularities. At the time of manufacturing, it is desirable to prepare a desired binder material first and knead it with a predetermined amount of aggregate. However, in order to speed up the construction, the rheological state in which the binder to which the admixture has been added has not yet solidified can be confirmed and kneaded together with the aggregate used.

The sound absorption coefficient was measured by using a sound absorption coefficient measuring device manufactured by B & K (Bruer Quayle Co., Ltd.) according to JIS A 14
05 "Measurement method for normal incidence sound absorption coefficient of building materials by pipe method"
According to the above, the thickness of the specimen was changed to 5, 7.5 and 10 cm, respectively. Figure 3 shows the relationship between sound absorption frequency and sound absorption coefficient.
It shows in (A).

The above mixture was packed in a mold having a diameter of 5 cm and a height of 10 cm, and after 2 days, it was demolded and wet-cured.
The compressive strength on a day was 35 to 37 kgf / cm ² .

A general traffic noise frequency is set to 400 hertz (Hz) to 1600 (Hz), and a sound absorbing plate that covers these frequency bands is desirable. Especially, the characteristics of absorbing sound of 400 Hz to 1000 Hz, which has a large influence, will be examined. Three plates with a thickness of 5 cm, 7.5 cm, and 10 cm using the mixed concrete are 400 Hz to 100 Hz.
The area ratio of sound absorption at 0 Hz was 80.5%, which was a considerably high sound absorption coefficient.

Next, in the concrete of the above composition,
Aluminum powder to cement as a bubble generator 1
FIG. 3 (B) shows the results of a similar experiment performed on a sound absorbing plate made of this concrete, using a mixture with a% added.

From these results, it can be seen that the peak frequency of the plate with each thickness changed moves to the high frequency side, but the sound absorption frequency band becomes wider and the sound absorption characteristics are improved.

The area ratio of three plates having thicknesses of 5 cm, 7.5 cm, and 10 cm that absorb sound of 400 Hz to 1000 Hz is:
This is 85.6%, and it can be seen that mixing of aluminum powder as a bubble generating agent is also effective from this point.

[0038]

Example 2 Carbon fiber (specific gravity:
(1.05, diameter: 0.007 mm, length: 5-7 mm) is mixed by 2% with respect to the volume of the binder, the sound absorption coefficient is changed from the noise frequency of 400 Hz to an area ratio of 1000 Hz to 4
Rose by ~ 5%. Further, as a result of a bending strength test of 4 × 4 × 16 cm, the bending strength was 9.2 kg / cm ² compared with 8.5 kg / cm ² for the non-mixed material, which was increased by 7% or more.

[0039]

As described above, according to the present invention, since it has the above-mentioned structure, the following effects can be obtained.

(I) Since the aggregates are bonded with the binder in an amount of 15 to 50% of the inter-aggregate voids, and continuous voids are formed between the aggregates wrapped with the binder, the acoustic energy penetrating into the voids is Since it can be converted into heat energy around the voids and efficiently absorb sound, it becomes concrete with excellent sound absorbing effect and can form a soundproof wall or sound absorbing plate that is cast on site.

(II) Since the binder contains the bubble-generating agent and foams, voids are generated, and acoustic energy also penetrates into the voids, so that the sound absorbing effect is further improved.

(III) As can be seen from the conventional sound absorbing concrete, it can be produced by sprinkling the cement-based binder containing the foaming agent on the aggregate without producing it by using heat such as autoclave curing. In addition, the bulk specific gravity of the concrete member used as a product is low when a lightweight aggregate is used, and it becomes a sound absorbing concrete plate having relatively high strength.

(IV) When the porous aggregate having continuous voids is used as the aggregate, it is possible to provide a sound absorbing concrete plate which is continuous with the voids of the binder and has further improved sound absorbing characteristics.

(V) By using the fibrous material together,
It is possible to provide a sound-absorbing concrete plate with further improved product strength and sound-absorbing characteristics.

(VI) By alternately changing the plate thickness, it is possible to provide a concrete product in which the frequency band for absorbing sound can be freely selected.

(VII) By using a volcanic stone such as pumice from Kagoshima as an aggregate, effective use of resources can be achieved.

[Brief description of drawings]

1A is a cross-sectional view of a sprinkled concrete using an aggregate as a porous binder, FIG. 1B is a cross-sectional view of a sprinkled concrete using a porous aggregate and a porous binder, and FIG. Cross-sectional view of dusted concrete mixed with single fiber

FIG. 2 (A) is a plan view of a sound absorbing concrete plate, and FIG. 2 (B).
Is a sectional view taken along the arrow bb of (A), and (C) is a sectional view taken along the arrow cc of (A).

FIG. 3A is an explanatory diagram showing the relationship between the sound absorption frequency and the sound absorption rate in a graph, and FIG. 3B is an explanatory view showing the relationship between the sound absorption frequency and the sound absorption rate in the case where a bubble generating agent is added.

[Explanation of symbols]

1 aggregate 1a continuous void 2 binder 2a continuous void 3 continuous voids 4 fibrous materials 5 concrete boards 6 convex 7 recess

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // (C04B 28/02 C04B 14:02 B 14:02 14:16 14:16)

Claims (6)

(57) [Claims] 1. A main material such as water, cement, a bubble generating agent,
A water-reducing agent is used, and in some cases, a polymer emulsion, a viscous polymer mixture such as an acrylic or cellulosic material, or a fine pozzolanic substance is added, and the mixture is used as a binder. A sound absorbing feature characterized by forming continuous voids between the aggregates by joining the aggregates with the binder in an amount of 15 to 50%, and the binder has voids inside due to foaming. Concrete. 2. Water, cement, a bubble generating agent as a main material,
A water-reducing agent is used, and in some cases, a polymer emulsion, a viscous polymer mixture such as an acrylic or cellulosic material, or a fine pozzolanic substance is added, and the mixture is used as a binder. A molded body is formed by binding aggregates using the binder in an amount of 15 to 50%, and continuous voids are formed between the aggregates, and the binder has voids inside due to foaming. Sound absorbing concrete secondary product. 3. A secondary sound-absorbing concrete product, wherein the aggregate of claim 2 has large irregularities on the surface selected from volcanic rubble, pumice stone and artificial lightweight aggregate. 4. The aggregate according to claim 2, which has continuous voids inside, selected from volcanic rubble, pumice stone and artificial lightweight aggregate, and the voids of the aggregate and the binder. Secondary sound-absorbing concrete products that are in communication with each other. 5. The sound absorbing concrete secondary product according to claim 2, wherein a fibrous material is mixed or laid in the binder. 6. The secondary sound-absorbing concrete product according to claim 2, wherein the plate thickness of the plate-like body formed by joining the aggregates with a binder is changed by the unevenness of the surface.